Two rapes, including one that of an attaché in the consular section of the Swiss embassy, have been reported from Delhi since Tuesday night.
The incidents, a week after the rape of a college girl in a park by four army jawans, have sent shockwaves across the capital.
The assault on the Swiss official, aged 35, took place when she was leaving the Siri Fort Auditorium after watching a movie at the International Film Festival of India at around 2200 IST, Tuesday, police said.
As she entered her car in the parking lot of the auditorium, two men forced themselves into the vehicle. One of them raped her as the vehicle was driven through South Delhi streets, the police said.
The victim was later dumped in Safdarjung Enclave, about five kilometres from the auditorium, they added.
A case has been registered at the Hauz Khas police station.
Earlier reports had said that the victim was a diplomat's daughter.
The external affairs ministry is in touch with the embassy.
The second rape was that of a nine-year-old girl in northwest Delhi, the police said. Details of that case are yet to emerge.
Within half-an-hour of the incident near the auditorium, an Indian woman filmmaker was robbed of her bag in the same parking lot, Police Commissioner R S Gupta said.
The woman, who suffered head injuries after struggling with the robbers, has been admitted to the Appollo Hospital, he added.
Gupta and Lieutenant Governor Vijai Kapoor visited the auditorium and assured that action would be taken against the culprits.
Four teams have been formed to track down the culprits, Gupta said, adding some clues have been obtained.
He said five police personnel, including an inspector, who were on duty at the parking lot, have been suspended for not being alert.
The commissioner also announced a reward of Rs 50,000 for any information about the culprits.
"We consider this a very serious issue... not just because it happened at the film festival," Kapoor said.
Kapoor conceded that rape cases in Delhi have shown an increase and said steps are being taken to ensure safety of all citizens.